Eur Radiol (2009) 19: 2584–2585DOI 10.1007/s00330-009-1564-6 CARDIAC

Filippo Cademartiri

Received: 20 July 2009Accepted: 23 July 2009Published online: 4 September 2009# European Society of Radiology 2009

Cardiac CT: the missing piece of the puzzle

Until a few years ago, conventional coronary angiographywas the only technique which could explore coronaryarteries. Although magnetic resonance imaging offeredsome promise, computed tomography coronary angiogra-phy (CTCA) really opened a window for the non-invasiveassessment of the coronary arteries. CTCA has rapidlybecame a real clinical tool, albeit with some importantlimitations (e.g. radiation dose and heart rate). Finally,CTCA is becoming a routine part of chest CT.

The paper deals with the clinical validation of a newCTCA geometry [1]. Compared with all previous algo-rithms, in this case the CT algorithm/geometry is a“hybrid”. First, there was electron-beam CT with prospec-tive ECG triggering. Then, there was spiral CT withretrospective ECG gating. Recently, prospective ECGtriggering was introduced to reduce the radiation dose.With this “prospectively ECG-triggered high-pitch spiralacquisition”, the two optimal techniques of cardiacsynchronization are merged together [2]. In order toachieve this CT geometry, a mandatory requirement isextremely high temporal resolution (to provide the mini-mum of 180° required for one image), which for CT means<100 ms (in hardware). The average radiation dose for such

CTCA is 0.8-0.9 mSv, the lowest ever reported. This wasfirst possible with dual-source CT systems, but all CTmanufacturers are coming up with their own solutions.

One major limitation still remains for CTCA, which isrelated to heart rate. In order to obtain the best imagequality, a low and regular heart rate should be achieved(probably <60-65 bpm). However, this is nothing new,since all the development of CTCA has been performedwith the extensive and aggressive use of beta-blockers [3].For all generations of CT technology, the statementconcerning heart rate, “the lower the better”, has been amantra for CT users. In addition, the re-introduction ofprospective ECG triggering recently determined a “revi-val” of beta-blockers.

This newmode for CT data acquisition is a revolution andmay cause another paradigm shift. In other words: thepossibility to examine the heart with 0.8-0.9 mSv (within∼300ms in total) and/or the possibility to examine the thoraxwith 1.2-1.4 mSv and have data about the heart “for free”.With this technology, any chest CT may become a CTof theheart with a radiation exposure lower than ever before. In thecardiology community this will require some time to beunderstood. Within radiology, this is even more usual. Just

This commentary refers to the articledoi:10.1007/s00330-009-1558-4

F. Cademartiri (*)Department of Radiology,Azienda Ospedaliero-Universitariadi Parma,Parma, Italye-mail: filippocademartiri@hotmail.com

F. CademartiriDepartment of Radiology,Erasmus Medical Center,Rotterdam, The Netherlands

think about what happened with the introduction of multi-slice CT. At that time a CTangiogramwas something specialwith specific CT protocol requirements. Afterwards, anychest/abdominal CT potentially became a CT angiogram(when performed in the arterial phase). Until 2000, the heartwas the missing piece from the puzzle. Now the puzzle

can be completed. In order to complete it, we need theradiology community to understand that cardiac imagingis going to be part of routine clinical practice and the corecurriculum of most radiologists. In a few years from nowit is likely that a standard report of chest CT will includethe description of the heart and coronary arteries.

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References

1. Achenbach S, Lell MM, Marwan M,Schepis T, Pflederer T, Anders K, FlohrT, Allmendinger T, Kalender WA, ErtelD, Thierfelder C, Kuettner A, RopersD, Daniel W (2009) ProspectivelyECG-triggered high-pitch spiral acqui-sition for coronary CT angiographyusing dual source CT: technique andinitial experience. Eur Radiol.doi:10.1007/s00330-009-1558-4

2. Ertel D, Lell MM, Harig F, Flohr T,Schmidt B, Kalender WA (2009)Cardiac spiral CT with high pitch: afeasibility study. Eur Radiol.doi:10.1007/s00330-009-1503-6

3. Maffei E, Palumbo AA, Martini C,Tedeschi C, Tarantini G, Seitun S,Ruffini L, Aldrovandi A, Weustink AC,Meijboom WB, Mollet NR, Krestin GP,de Feyter PJ, Cademartiri F (2009) “In-house” pharmacological managementfor computed tomography coronaryangiography: heart rate reduction, tim-ing and safety of different drugs usedduring patient preparation. Eur Radiol.doi:10.1007/s00330-009-1503-6